1. Field of the Invention
The present invention relates to an ink jet recording device that ejects ink from nozzles to record on sheets and the like.
2. Description of the Related Art
One conventional ink jet recording device includes a head unit with an ink cartridge and an ink jet head. The ink cartridge holds ink and the ink jet head ejects the ink onto a sheet, for example, to record images on the sheet. The ink cartridge and the ink jet head are brought into fluid communication by a tube through which ink flows from the ink cartridge to the ink jet head. This can be referred to as a tube-supply type ink jet recording device.
FIG. 1 shows a conventional tube-supply type ink jet recording device. The device includes a head unit 1, a carriage 20 that supports the head unit 1, a subtank 26, and an ink cartridge 31 for supplying ink to the head unit 1.
The head unit 1 includes a head holder 2, an ink jet head 3, a buffer tank 4, tubes 15, 16, and a head-side joint member 5.
The ink jet head 3 includes an actuator 6 and a manifold 7. The actuator 6 is formed with a plurality of ejection channels (not shown) for ejecting ink from a nozzle surface 8. The manifold 7 is connected to the upper end portion of the actuator 6 and is formed with an upwardly protruding ink-inflow port 10. The manifold 7 distributes ink from the ink-inflow port 10 to each of the ink channels in the actuator 6. The actuator 6 changes volume in the ink channels to eject ink vertically downward from the nozzle surface 8.
The head holder 2 is supported by the carriage 20 with a substantially horizontal orientation. The head holder 2 supports the ink jet head 3 through an attachment plate 11 that is fixedly attached to the manifold 7. The head holder 2 includes a head cover 9 that covers the ink jet head 3 in a condition with the nozzle surface 8 exposed facing vertically downward.
The buffer tank 4 serves as a vessel for temporarily holding ink. The buffer tank 4 is supported by the head holder 2 at a position above the ink jet head 3. The buffer tank 4 is formed at its lower portion with a downwardly protruding ink-outflow port 14, and at its upper side with an upwardly protruding ink-supply port 12 and an upwardly protruding ink-return port 13. The ink-outflow port 14 is connected to the ink-inflow port 10 of the manifold 7. With this configuration, ink held in the buffer tank 4 is supplied from the ink-outflow port 14 to the manifold 7 through the ink-inflow port 10. The ink-supply port 12 is connected to the inner supply tube 15 and the ink-return port 13 is connected to the inner-return tube 16.
The head-side joint member 5 includes a head-side-supply joint 18 and a head-side-return joint 19 that are aligned next to each other on, and that protrude vertically upward from, the head holder 2. The head-side-supply joint 18 and the head-side-return joint 19 are each formed in a hollow-tube shape. The head-side-supply joint 18 and the head-side-return joint 19 are connected at the top end to the inner supply tube 15 and the ink-return port 13, respectively, and are open downward.
The carriage 20 includes a casing 21 and a carriage-side joint member 22. The casing 21 houses the head unit 1 and supports the head unit 1 and the carriage-side joint member 22 with substantially a horizontal orientation. The carriage-side joint member 22 is provided on the casing 21 and includes a carriage-side-supply joint 23 and a carriage-side-return joint 24. The carriage-side-supply joint 23 and the carriage-side-return joint 24 are formed in a hollow-tube shape and protrude vertically upward. The carriage-side-supply joint 23 and the carriage-side-return joint 24 are inserted in the head-side-supply joint 18 and the head-side-return joint 19, respectively, to connect to the head-side-supply joint 18 and head-side-return joint 19.
The carriage-side-supply joint 23 is connected to subtank 26 through an outer-supply tube 27 and the carriage-side-return joint 24 is connected to the subtank 26 through an outer-return tube 28. A circulation pump 29 is provided along the outer-return tube 28.
When the circulation pump 29 is driven, ink held in the subtank 26 is supplied to the buffer tank 4 through the outer-supply tube 27, the carriage-side-supply joint 23, the head-side-supply joint 18, the inner supply tube 15, and the ink-supply port 12. Simultaneously with this, ink held in the buffer tank 4 is returned to the subtank 26 through ink-return port 13, the inner-return tube 16, the head-side-return joint 19, the carriage-side-return joint 24, and the outer-return tube 28. Bubbles generated in the ink are collected in the subtank 26 with the ink, and naturally separate from the ink by the difference between weight of the bubbles and the ink in the subtank 26. The circulation pump 29 is normally not driven. Rather, the amount of ink that is ejected by the ink jet head 3 is naturally supplied from the subtank 26 to the buffer tank 4 through the outer-supply tube 27 by force of capillary action that operates in the nozzle portion of the actuator 6.
The ink cartridge 31 is connected to the subtank 26 through a supplementary tube 30. Also, a liquid-feed pump 32 is provided along the supplementary tube 30. The liquid-feed pump 32 normally supplies ink from the ink cartridge 31 into the subtank 26 in accordance with reduction in the amount of ink held in the subtank 26.
The head-side-supply joint 18 and the carriage-side-supply joint 23, and the head-side-return joint 19 and the carriage-side-return joint 24, extend in substantially the same direction in which the ink jet head 3 ejects ink, and moreover, are connected in a vertical direction that is substantially perpendicular to the direction in which the head unit 1 is supported on the casing 21. Therefore, the tubes 15 and 16 need to be bent around at an approximately 180xc2x0 angle in order to connect the tubes 15 and 16 to the joints 18 and 19. For this reason, the tubes 15 and 16 need to be made from an extremely flexible material. This places an inconvenient limitation on materials that can be used to form the tubes 15 and 16.
Also, the tubes 15 and 16 need to be rather long because the distance between connection ends of the tubes 15 and 16 increases when the tubes 15 and 16 are bent around at an approximately 180xc2x0 angle. As a result, more material is required to produce the tubes 15 and 16, so material costs increase. Also, the amount of ink that needs to be circulated increases. Production costs increase because a more powerful pump is required and running costs increase because the more powerful pump requires more energy to run. Also, because flexible tubes are normally semi permeable to air, a great amount of air penetrates through the walls of the tubes 15 and 16 because the tubes 15 and 16 are so long. More bubbles are generated so the possibility of defective ejections in the ink jet head 3 also increases.
Because the joints 18 and 19 are aligned next to each other on, and protrude vertically upward from, the head holder 2, it is impossible to secure a sufficient pressure head, even though the head-side joint member 5 is supported on the head holder 2 at a position that is higher than the ink jet head 3. Ink can be drip out from the joints 18 and 19 after the joints 23, 24 detach from the joints 18 and 19 when the head unit 1 is detached from the carriage 20.
Because the joints 18 and 23, and the joints 19 and 24, have a substantial vertical orientation when connected to each other, the head holder 2 and the carriage 20 need to be wider by an amount equal to the width of the joints 18, 23, 19, and 24. Therefore, the silhouette of the head unit 1 is larger, so that the ink jet recording device is larger, and manufacture, transport, and storage are less convenient.
It is an objective of the present invention to overcome the above-described problems and provide an ink jet recording device including a head unit that has no limitations on the material of the inner-supply tube and the inner-return tube so that production costs and running costs can be reduced, that has fewer ink drips when the head unit is detached, and further that has a small silhouette.
In order to achieve the above-described objectives, an ink jet recording device according to one aspect of the present invention includes a head unit and a support member. The head unit includes a head member and a head-unit-side connection member. The head member ejects ink in a predetermined direction. The head-unit-side connection member is formed with a first channel in fluid connection with the head member for supplying ink to the head member. The support member detachably supports the head unit and includes a support-member-side connection member formed with a second channel. While the support member supports the head unit, the support-member-side connection member and the head-unit-side connection member are connected to each other with the second channel and the first channel in fluid communication and extend in a substantial linear relationship at an acute angle with respect to the predetermined direction of ink ejection by the head member.
An ink jet recording device according to another aspect of the present invention includes a head unit and a support member. The head unit includes a head member for ejecting ink and a head-unit-side connection member formed with a first channel in fluid connection with the head member for supplying ink to the head member. The support member detachably supports the head unit and includes a support-member-side connection member and a support surface. The support-member-side connection member is formed with a second channel. The support surface extends in a predetermined direction to provide sufficient surface area to support the head unit. While the support member supports the head unit, the support-member-side connection member and the head-unit-side connection member connected to each other with the second channel and the first channel in fluid communication and extend in a substantial linear relationship at an acute angle with respect to the predetermined direction in which the support surface extends.
An ink jet recording head according to one aspect of the present invention includes a head member, an inlet member, and a connection member. The head member ejects ink. The inlet member is provided on the head member and protrudes away from the head member in a predetermined direction. The connection member is for connecting with an external ink source to receive ink from the external ink source. The connection member is in fluid connection with the inlet member and extends in a direction at an acute angle with respect to the predetermined direction in which the inlet member protrudes.
An ink jet recording head according to another aspect of the present invention includes a head member and a connection member. The head member includes a nozzle surface that extends in a predetermined direction. The nozzle surface is formed with nozzles that eject ink. The connection member is for connecting with an external ink source to receive ink from the external ink source. The connection member is in fluid connection with the inlet member and extends in a direction at an acute angle with respect to the predetermined direction in which the nozzle surface extends.